Two wheeled self-balancing vehicles generally have two coaxial wheels spaced a distance apart. Each wheel is controlled by a separate electric motor. The control systems for these vehicles receive inputs from gyroscopes and accelerometers to determine the pitch angle of the vehicle and generate appropriate outputs to the wheel driving motors to dynamically stabilize the vehicle. U.S. Pat. No. 5,971,091 describes such a system. To turn the vehicle, the control system biases the outputs to the two motors such that one motor turns faster than the other.
The majority of self-balancing vehicles require the operator to be in a standing position, usually with a handlebar positioned in front of the operator that the operator uses to steer the vehicle. With these vehicles, forward and backward motion is initiated by the operator pushing forward.
Some earlier self-balancing vehicles were steered by twisting a grip on the handlebar. U.S. Pat. No. 6,581,714 describes this method. Some later versions are steered by leaning the entire handlebar assembly to the left or right. US patent application publication No. 2010/0250040 describes a method of steering a self-balancing vehicle where the operator uses his legs to push a vertical steering mechanism from side to side.
While the prior devices normally operate satisfactorily, they do not afford the user the ability to operate the vehicle from a seated position.